The invention relates generally to cartridges such as for ink jet printers, and in particular to restricting flash spread which can occur when welding housing portions of the cartridge together. In this context, the term xe2x80x9cflashxe2x80x9d is a well known one, meaning the excess material that can spread from a weld.
The cross-referenced applications filed Aug. 16, 2001 disclose an ink cartridge including a pair of housing halves that have an opening at a seam formed by respective abutting edges of the housing halves. A memory chip is supported within the opening to permit electrical contact to be made with the memory chip. A number of protuberances project from one of the housing portions and are welded to the other housing portion within respective cavities in the other housing portion. It is a concern that a flash formed when welding any one of the protuberances to the other housing portion might spread from the weld towards the seam including in the vicinity of the opening for the memory chip.
If the flash spreads too far, it might lodge between the edges of the housing halves that must abut to form the seam. This can interfere with abutment of the edges to form the seam.
Also, the flash may bulge outward from the seam in the vicinity of the opening for the memory chip, which could present an obstacle to making electrical contact with the memory chip.
These problems are believed to be solved by the invention.
According to one aspect of the invention, a cartridge comprising one housing portion having a protuberance adhered to another housing portion at a weld within a cavity in the other housing portion and which results in a flash being formed at the weld capable of spreading towards respective edges of the housing portions that abut to form a seam between the housing portions, is characterized in that:
the protuberance and the cavity are mutually dimensioned to restrict the flash substantially to within the cavity in order to prevent the flash from spreading between the edges of the housing portions, since if the flash was to spread between the edges it could interfere with their abutting to form the seam.
According to another aspect of the invention, a method of restricting spread of a flash from a weld formed when a pair of housing portions of a cartridge are welded together, comprises:
providing one of the housing portions with a protuberance that fits into a cavity in the other housing portion, but has an original length that is long enough to prevent edges of the housing portions from abutting to form a seam;
inserting the protuberance into the cavity;
melting a tip of the protuberance sufficiently by welding to reduce the length of the protuberance in order that the edges of the housing portions can abut to form the seam; and
providing sufficient space in the cavity for the flash to spread from the weld without reaching the edges of the housing portions.
According to another aspect of the invention, a cartridge comprising a pair of housing portions having an opening at a seam between the housing portions, a memory chip accessible via the opening to permit electrical contact to be made with the memory chip, and a protuberance projecting from one of the housing portions and welded to the other housing portion within a cavity of the other housing portion and which results in a flash being formed at the weld that can spread towards the seam including in the vicinity of the opening, is characterized in that:
the protuberance and the cavity are mutually dimensioned to restrict the flash substantially to within the cavity in order to prevent the flash from bulging outward of the seam at least in the vicinity of the opening, since if the flash was to bulge outward of the seam in the vicinity of the opening it might present an obstacle to making electrical contact with the memory chip.